#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>
#include <cstdlib>
#include <cmath>

using namespace std;
const long long convert = 1e10;

int main() {
	int n;
	string s;
	long long ans1 = 0; // 整数部
	long long ans2 = 0; // 小数部
	long long tmp;

	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> s;

		int pos = s.find('.', 0);
		ans1 += atoll(s.substr(0, pos).c_str());

		if (pos != string::npos) {
			tmp = atof(s.substr(pos).c_str()) * convert;
			// ans2 += (long long) (s[0] == '-' ? -tmp : tmp);
			// (s[0] == '-') ? ans2 += tmp : ans2 -= tmp;
			if (s[0] == '-') {
				ans2 -= (long long)tmp;
			} else {
				ans2 += (long long)tmp;
			}
		}

// printf("%23s %13lld %13lld %13lld\n",
// 		s.c_str(),
// 		atoll(s.substr(0, pos).c_str()),
// 		pos == string::npos ? 0 : tmp,
// 		ans2
// 		);
	}

// printf("a %lld %lld\n", ans1, ans2);
// cout << 1.0 * ans2 / convert << endl;
	// 0 <= ans2 < 1e10 にする
	if (ans2 < 0) {
		ans1 += floor(1.0 * ans2 / convert);
		ans2 -= floor(1.0 * ans2 / convert) * convert;
	} else {
		ans1 += ans2 / convert;
		ans2 -= ans2 / convert * convert;
	}
// printf("b %lld %lld\n", ans1, ans2);
	// ans1 ans2の符号を同じにする
	if (ans1 < 0 && ans2 > 0) {
		ans1++;
		ans2 -= convert;
	}
// printf("c %lld %lld\n", ans1, ans2);

	if (ans1 == 0 && ans2 < 0) {
		printf("-");
	}
	printf("%lld.%010lld\n", ans1, abs(ans2));
	return 0;
}